When a coating material is coated on a surface of plastic articles, etc., such phenomena as color separation, remaining of foams, poor leveling, poor wetting etc. often occur. To prevent these phenomena, additives such as silicone resin etc., which decrease surface tension of the coated layer, have been beforehand added into the coating material.
Japanese Patent Provisional Publication No. 09-255754 discloses a silicone type polymer that is added, as a leveling agent and/or defoaming agent for paint into a cure type composition.
However, in this case, over-coatability onto a coated layer or anti-fouling property of the coated layer tends to be deteriorated when the surface tension of the coated layer is substantially lowered.
The present invention is made to solve the above mentioned problems. An object of the present invention is to provide a surface tension control agent for coating materials, which are used for suitably controlling a surface tension of a coated layer of the coating material and giving the coated layer an excellent over-coatability and/or anti-fouling property, and a coating material containing the same.